The first cousin of your dad's first cousin is also your your dad's first cousin or is not related to him or to you. The children of two first cousins are second cousins to each other.
So the son of the first cousin of your dad's first cousin is either your second cousin, or is not related to you at all.
Your father's first cousin's children are your second cousins. Put another way, you share a common great-grandparent, and this makes you second cousins.
The children of your father's second cousins are your third cousins.
The children of your father's third cousins are your fourth cousins.
The son of your father's first cousin is your second cousin.
Your dad's sister's son's son is your first cousin once removed, or simply your cousin.
You are each others cousins.
First cousins twice removed.
They are your cousins.
You and your first cousin's children are first cousins once removed. Your children are their second cousins.
Your children are the first cousins of your brother's children, and the first cousins once removed of your brother's grandchildren.
You and your second cousin's children are second cousins, once removed. Your children and your second cousin's children are third cousins.
Your child and your sister's children are first cousins. Your grandchild and your sister's children are first cousins once removed.
Your children and your nephew's children are frst cousins, once removed
Anyone descended from a brother or sister of one of your direct ancestors is your cousin. There are different names for different kinds of cousins. For example, your first cousins are the children of your aunts and uncles. Your second cousins are the grandchildren of your great aunts and great uncles. Your parents'first cousins are your first cousins, once removed. And the children of your first cousins are also your first cousins, once removed.
Your sister's children's children are her grandchildren.Your children and your sister's grand children are first cousins, once removed.Your grandchildren and your sister's grandchildren are second cousins.
Your granddaughter and your first cousin's grandson are third cousins to each other. You find their common ancestor that is, your grand parents, and count the number of generations separating them, there are Brother and Sister then cousins, you and your cousin would be one (first cousins), your children and your cousins children are second cousins and their children are third cousins and so on.
The children of your father and the children of your father's first cousin are second cousins to each other. The children of your father and the children of your father's second cousin are third cousins to each other.